1. Field of the Invention
This invention relates to an outboard motor, more particularly to an outboard motor whose power source can be freely changed among an internal combustion engine, electric motor and combination thereof.
2. Description of the Related Art
Among outboard motors, there are known three kinds of outboard motors, i.e., one equipped with an internal combustion engine as its propeller power source, another equipped with an electric motor as its power source and, as taught, for example, by Japanese Laid-Open Patent Application No. Sho 59(1984)-230,894 (page 2, left column, line 9 to 13, FIG. 1, etc.), the other equipped with a combination of an internal combustion engine and an electric motor as its power source (hybrid outboard motor). One of the above three kinds of power sources is mounted on a boat (hull) to be used.
However, outboard motor power sources are different in their characteristics each other, for instance the internal combustion engine has good high-speed performance, the electric motor has a characteristic of quietness, and the like. Therefore, there is a demand for easily changing an outboard motor power source to be mounted.